The purpose of this project is to examine the effects of heart failure on aortic and mitral valve function in the dog. To accomplish this the valve leaflets will be made radiopaque by placing a thin coat of a viscous, radiopaque, gelatin solution on the distal surfaces of the valve cusps. Once coated the motion of the cusps will be recorded on cine film at 500 frames per second using cineradiography. While the film is being taken intracardiac and aortic pressures along with the electrocardiogram will be recorded on magnetic tape. A computerized X-Y digitizing tablet will be used to analyze the cusp motion as the films are projected frame by frame. Analog to digital converters will be used to digitize the analog parameters. Acute heart failure will be created in three ways: 1) through volume overload by infusion of large volumes of dextran, 2) through pressure overload by infusion of the alpha agonist methoxamine, and 3) through reduction of contractility by administration of the anesthesia, halothane. We are particularly interested in finding a) how heart failure affects the volocity and timing of opening and closing of the valve leaflets, b) whether the way in which the heart failure is produced can be distinguished by analysis of valve function, and c) whether reliable estmates of ventricular mechanical function can be obtained from indices of valve function. Such information will increase the knowledge of the natural history of heart failure and may help further the usefulness of techniques already used clinically to evaluate cardiac valve function, such as echocardiograhy.